Process of desulphurizing artificial silk of viscose



Patented Aug. 30, 1938 UNITED STATES PROCESS OF DESULPHURIZING ARTIFI- CIAL SILK F VISCOSE Emil Hubert, Dessau-Ziebigk, and Hermann Hecht, Dessau, Germany, assignors to I. G.

Farbenindustrie Aktiengesellschaft,

Frankfort-on-the-Main, Germany No Drawing. Application October 10, 1935, Serial No. 44,462. In Germany October 13, 1934 6 Claims.

Our present invention relates to a process of desulphurizing artificial silk from viscose.

One of its objects is an improved process of desulphurizing artificial silk from viscose. Further objects will be seen from the detailed specification following hereafter.

We have found that artificial silk spun from viscose to which a Wetting agent soluble in the viscose has been added can be desulphurized in the usual after-treatment by the mere treatment with a soap solution at a temperature of 15 to 25 0. Such wetting agents are particularly the sodium xanthates of the higher aliphatic alcohols, aromatic alcohols, hydroaromatic alcohols, cyclic and heterocyclic alcohols, for instance, the sodium xanthates of octylalcohol, of decylalcohol, of borneol, of mental, of fenchyl alcohol, of furfuryl alcohol, of naphthene alcohol, of dekahydronaphthol, of methylcyclohexanol, of hexahydroisothymol, of phenyl-ethyl alcohol and of phenylpropyl alcohol; alkylated and alkoxylated arcmatic and hydroaromatic sulphonic acids, for instance, benzylnaphthalenesulphonic acid, diisopropylbenzenesulphonic acid, dialky1naphtha lenesulphonic acid and dodecylnaphthalenesulphonic acid; alcohols such as glycerine and glycol; unsaturated organic compounds, for instance, allyl alcohol, cinnamic alcohol, acrylic acid, crotonic acid, soya-oleic acid, and the sodium salt of 30 benzenesulphinic acid; cholic acid, glycocholic acid, naphthenic acid, and the salts and derivatives of these acids; sulphonated castor oil and the salts of the sulphonated products. The compounds are added to the viscose in an amount of 0.1 to 0.3% calculated on the viscose. The compounds are suitable for desulphurization of artifi cial silk made from any viscose, ripened viscose as well as unripened viscose. The viscose is spun in the usual manner and after-treated while omitting the usual desulphurizing bath. Contrary to the usual practice the soap bath is not heated but is used at a temperature of 15 to 25 C. The usual soap baths may be used, for instance, sodium oleate, Monopol Oil (registered trade-mark) or Marseilles soap (registered trade-mark) The artificial silk may be treated in the form of hanks or on spools or cops. In the latter case the liquid is forced through the windings by pressure or suction.

EmampZa-A viscose made from sulphite cellulose and containing 7.5 per cent of cellulose, 6.5 per cent of sodium hydroxide and 0.25 per cent of the sodium salt of borneoyl xanthate is spun to artificial silk in a bath containing 13 per cent of sulphuric acid and 30 per cent of Na2SO4. The spun fibers are washed free from acid and treated with a solution of the sodium salt of sulphonated olive-oil of 0.75 per cent strength at 20 C. in the course of 1 hours, whereby they are completely desulphurized. Instead of the sodium salt of borneol xanthate the viscose may also contain 0.3 per cent of Turkey red oil or 0.2 per cent of sodium alkyl-naphthalene-sulphonate.

What we claim is:

1. A process of desulphurizing artificial silk which comprises dissolving in viscose 0.25 per cent of sodium borneol xanthate, spinning said viscose into a precipitating bath, Washing the threads thus obtained free from acid and desulphurizing the deacidified threads only by treatment with a 0.7 per cent solution of the sodium salt of sulphonated olive-oil at 20 C. for 1 hours.

2. A process of desulphurizing artificial silk which comprises dissolving in viscose 0.3 per cent of Turkey red oil, spinning said viscose into a precipitating bath, washing the threads thus obtained free from acid and desulphurizing the deacidified threads only by treatment with a 0.7 per cent solution of the sodium salt of sulphonated olive-oil at 20 C. for 1 hours.

3. A process of desulphurizing artificial silk which comprises dissolving in viscose 0.2 per cent of sodium alkyl-naphthalene-sulphonate, spinning said viscose into a precipitating bath, washing the threads thus obtained free from acid and desulphurizing the deacidified threads only by treatment with a 0.7 per cent solution of the sodium salt of sulphonated olive-oil at 20 C. for 1 hours.

4. A process of desulphurizing artificial silk which comprises incorporating in viscose a wetting agent soluble in viscose, spinning said viscose into a precipitating bath, washing the threads thus obtained free from acid, and desulphurizing the deacidified threads only by treatment with a soap solution at 15 to 25 C.

5. A process of desulphurizing artificial silk which comprises incorporating in viscose a sodium xanthate of a cyclic alcohol soluble in the viscose, spinning said viscose into a precipitating bath, washing the threads thus obtained free from acid, and desulphurizing the deacidified threads only by treatment with a soap solution at 15 'to 25 C.

6. A process of desulphurizing artificial silk Which comprises incorporating in viscose a salt of an alkylated aromatic sulphonic acid soluble in the viscose, spinning said viscose into a precipitating bath, washing the threads thus obtained free from acid, and desulphurizing the deacidified threads only by treatment with a soap solution at 15 to 25 C.

EMIL HUBERT. HERMANN I-IECI-IT. 

